Tables are used in protocol specifications, especially in specifying protocol state transitions. By laying out information in two dimensions (rows and columns), a reader can more easily gain a bird's-eye view from tables than from text. Further, the two-dimensional structure of tables also makes it easier to spot missing conditions in tables than in texts, so tables are more likely to be complete than texts. Changes to a protocol can typically be realized as localized changes to specific rows and/or columns in the tables, as opposed to diffused and unstructured changes in a text-based specification. However, tables in traditional specifications are informal and their potentials not fully utilized.